Tube commutator



Aug. 23, 1932. R. H. RANGER 1,873,785

TUBE COMMUTATOR Filed April 11, 1928 2 Sheets-Sheet l INVENTOR R.H.RAN11 BY 2M ATTO EY aqua 1' IMNNE l Aug. 23, 1932. R. H. RANGER 785 TUBECOMMUTATOR Filed April 11. 1928 2 Sheets-Sheet 2 INVENTOR R.H. RANGER J/LK/MW TTORNEY Patented Aug. 23, 1932 PATENT RICHARD ROWLAND RANGER, orNEWARK, new JERSEY, ASSIGNOR T0 'nAnIo conroan'rron or. AMERICA, Aooaronnrron or DELAWARE TUBE COMMUTATOR Application filed April 11,

The present invention relates to signalling systems and particularly tosignalling systems wherein a plurality of signals are to be transmitted,and to a method and means for multiplexing the various signals for'transmission.

A principal object of my invention is to provide a tube commutatorsystem whereby it is possible to utilize only vacuum tubes forcommutation in a system for either picture of facsimile transmission,multiplexing or for television on a multiplewave communication system.

A further object of my invention is to producea commutator systemwherein it is possible to transmit pictures or facsimile or to utilizethe system for television or a plurality of speech communications on aplurality of separate electro-magnetic Waves, in which the commutation,or switching from one signal channel to another, is accomplished bymeans of delayed action vacuum tubes without the use or aid of anymechani terrupted manner than is possible with mechanical commutation,since with the latter it has always been necessary to stop thetransmitting arrangement at frequent intervals for the purpose ofchanging the brushes on mechanical commutators.

A still further object of my invention is to provide a tube commutatingsystem .for utilizing a plurality vof bands of difierent frequencies forwire or radio communication, in which the tube commutating system isabsolutely and totally independent of the use of any relays foraccomplishing the channeling or switching from one frequency to another.j

A'still further. object of my invention is 1928. Serial No. 269,099.

to control the time elements in the severalchannels ofcommunication'which may be preferably accomplished by the use ofcondensers charging through vacuum tubes and preferably having theirdischarge rate a0- centuated or retarded by reason of thechar-' acter ofthe signal pulse or by a neon lamp, or any other type of glow dischargelamp whichiis found suitable, for aiding or retarding the rapiddischarge of the condenser and speeding or slowing the time of passageof electrical impulses through each separate channel.

A still further object of my invention is to provide a tube commutator,or rotary oscillator, in which the time period of signalling througheach channel isregulated, so that if only one channel has a signal atthe par- I ticular instant'it may utilize practically the entire timeavailable for all channels irrespectlve of the other channels in thecommu tating system, in contrast to schemes heretofore known, where thetime was divided equally between all of aLseries of separatecommunication channels. v

Still a further object of the invention'is to provide an arrangementwhereby it is possible to utilize a plurality of frequencies in thetransmission 'of pictures, facsimiles, speech or code, or a televisionsystem'and to provide at the same time a system which readily adaptsitself to the combining of the separate messages into a joint or.finished message ata' receiving point.

Still a further ob ect of my invention is to tion wherein it isextremely easy at anytime to increase the vnumber ofcommunicationchannels without the necessity of changing or altering thearrangement asinitially set the up, but by merely making additions to original set-up.

A still further object of my'invention is to provide an arrangementwherein great ease of maintenance is experienced.

Other objects of my invention will appear after a consideration of thefollowing description taken in connection with the accompanyingdrawings, and when the accompanying drawings are read in connec-'provide anarrangement for tube commutation with the appended claims.However, the invention also has for its objects those of providing atube commutating device which is simple in its construction andarrangement of parts, a system which is durable, compact, very efiicientin the use of the time for signaling available, a system which isconveniently operated, readily set up, and a system which may beinstalled at a minimum of expense, as well'as a system which is highlycapable of meeting the conditions of the future by its feature ofreadily adapting itself to the enlargement of the number of signalingchannels used.

The novel features which I believe to be characteristic of my inventionare set forth in the appended'claims. The invention itself, however,both as to its organization and method of operation together withfurther objects and advantages thereof will best be understood byreference to the following description read in connection with theaccompanying drawings wherein:

Fig. 1 represents one adaptation of my tube commutating system to asystem using four separate channels of communication and in which thesignals of the separate channels are introduced in the system throughmultiple grid connecting or modu lating tubes. Although, as shown, thesystem is applied to four signal channels, it will be readily seen howthe number could be increased to any number desired; and,

Fig. 2 is a modification of Fig. 1, in which only the usual threeelectrode tubes are used.

To consider the arrangement shown by Fig. 1 of the drawings, it isbelieved best to consider first the several channelsv for introducingthe separate signals into the commutator which are indicated broadly asA, which is composed of the tubes 1, 2, 3 and 4; B, which is composed ofthe tubes 6,7, 8 and 9; C, which is composed of tubes 11, 12, 13 and id;and lastly, as shown by the drawing, D, which includes the tubes 16, 17,18 and 19. Each of the separate channels A. B, C and D feed theiroutputs into separate amplifiers 5, 10, 15 and 20 respectively.

Now making specific reference to channel A, let it be firstconsideredthat the grid members 57, 58, 59 and 60 of the tubes 1, .2, 3 and 4 areall positive as well as the grid 61 of the tube 5, although thefunctioning of the tube 5 will bear no relationship at present, so faras the description of the various signal channels is concerned, to theoperation of my commutator arrangement for multiple channeling. At timeperiods when each of the grids above named are positive each of theseparate tubes in channel A tends to pass plate current. The plate 77 oftube 1 is supplied with plate voltage from a source of high potential33, the plate 7 8 of tube 2 is energized from a source 36a, the plate 79 of tube 3 is energized from a source 36, and, lastly, the plate oftube 4: is energized from a source of high potential 34. Underconditions when each of the separate tubes are passing plate current,and for the time being it will be unnecessary to consider the actionofthe grid 53 upon the tube 1 of channel A, the tube 1 tends to passcurrent and the condenser 21 which is connected across the filament andplate'lead to this tube has stored up energy so that at the time thetube tends to pass plate current the condenser 21 will tend to dischargedue to the sudden rush of current through the tube 1. At this time thepoint of connection of the resistance 25, which is a very highresistance and is connected in the leads from. the plate source 33supplying the plate 77 of tube 1 with a certain definite platepotential, will tend to become negative with respect to its previousvalue due to the voltage .drop occurring through the resistance and thefact that the condenser 21 is being discharged.

At the same time that tube 1 has its grid 57 positive the grids 58, 59and 60 of tubes 2, 3 and a which are connected to grid member 57 willalso be positive, and each of the tubes 2, 3 and 4c will likewise tendto pass plate current. As the tube l commences to pass plate current anegative potential is applied to the grid 62 of the tube 6 in channel Bby reason of the voltage drop in the grid resistor 30 of the tube 6 ofchannel B because tube 4 is drawing current from the plate source 34;which has its return connection through the filament of tube 6, andsimilarly the tube 3 drawing current from source 36 tends to cause thegrid 67 of tube 11 of channel C to become negative by virtue of theresistance drop in the grid resistor 31 of tube 11, and the tube 2drawing current from source 36a causes the grid 72 of tube 16 of channelD to become negative by virtue of the resistance drop across the gridresistor 32 of tube 16. This negative potential applied to the grids 62,67 and T 2 of the first tubes 6, 11 and 16 of channels B, C and D,respectively, causes a similar negative potential to be applied to thegrids of all the tubes in these respective channels because the grids ofthe various tubes in each channel are connected. This negative potentialcuts oil" the flow of plate current in all the tubes so that the outputof each separate channel excepting A is cut oli.

As has been above stated, as soon as the tube 1 commences to pass platecurrent the condenser 21 is discharged due to the tendency for a heavyrush of current to pass through tube 1 and a voltage drop occurs acrossthe heavy resistance 25 connected in series with the plate source 33which carries the point 93 to a negative value with respect to thepotential which it had an instantbeteams I enough to control the voltageon the grid 60V of the tube 4 so that the grid is carried to arelativelynegative potential with respect to its previous potential. Under thiscondition the current flow. through the tube 4 is decreased. I I

The tube 4 receives its plate current through a source of potential 34which also connects to the grid resistor 30 of the tube 6 and, as thefilaments of all tubes are in parallel, is efiectively connected withthe filament of tube 4. Upon a decrease in the flow of plate currentthrough tube 4, the grid 62 of the tube 6 is swung positive with respectto the previous potential because of thedecrease in the plate currentflow from plate 80, source 34, resistor 30 and the filament of tube 6,resulting in a decrease in voltage drop through resistor 30.Consequently, the grid 63 of the tube 7 which is directly associatedwith grid member 62 will also become positive with respect to theprevious potential and the tube 7 will tend to pass plate currentthrough the plate member 82, the source of plate potential 35, gridresistor 29 of tube 1 and the filament of tube 1. Upon such a condition,the grid 57 of the tube 1 will tend to become negative by virtue of thefact that the end of the grid resistor 29 of the tube 1 has changed froma positive-to a negative value due to the fact that plate current isbeing drawn through the-tube 7 from the battery 35. This will tendtomake the'grids 57, 58, 59 and 60 of tubes 1, 2, 3 and 4 respectivelv allmore strongly negative and will, therefore, i

tend to cut down the plate current drawn by the tube 4 even morestrongly than under the condition when the condenser'21 was dischargedand the point 93 had assumed a negative value. 'TlHS action of channel Bdrawing plate current w1ll, therefore, function as a locking feature forstopping the action of channel A and, as can be seen, the time of actionis governed in accordance with the rate of discharge of condenser 21.

As the tube 6 tends to draw plate current from source 33 due to the factthat the grid number 62 has become positive by reason of.

the decrease in the flow of the plate current through the tube 4 and thelocking action of tube 7 on channel A, and since the grids 63, 64 and oftubes 7, 8 and 9, have likewise become positive through connection togrid 62 of tube 6, each of the tubes in channel B will commence to passplate current. In channel B the tube 7 drawsits plate current fromsource 35, the tube 8 draws its plate current from the source36a and thetube 9 draws its plate current from the source 36 and, as before stated,the tube 6 draws its plate current from the source of B or platepotential 33. B of discharging of condenser 22 which Due toan action'inchannel is similar to the discharging of condenser 21 in channel A andthe voltage drop in the" resistance 26, connected in series with theplate 81 of the tube 6 and the B source 33, the

point 94 becomes negative with respect to its previous potential and bya similar action to that above describedin connection with channel A,the C battery 42 acting through the resistance 41 is now in control ofthe potential on the grid 65 of the tube 9 and carries the samenegative, so that the flow of plate I current through the plate 84 oftube 9, plate source 36, grid resistor 31, the filament of tube 11 andthus the filament of tube 9 is decreased, under which condition the grid67 of the tube 11 in channel C commences to swing toward a strongpositive value, due to the fact that the grid resistor 31 at the pointof connection to the grid 67 of the tube 11 is no longer negative sinceno voltage drop is occurring therethrough. This, therefore, Wllllikewise effect the grid members 68, 69 and 70 of the tubes 12, 13 and14 respectively, and, I

as can be readily seen after considering the above description asregards the operation of channels A and B, at the time when the tube 1201": channel C tends to pass plate current by virtue of the fact thatthe grid' member 68 hasbecome positive through its connection to grid67, the grid 62 of tube 6 of channel B has become negative due to.

than at first. In a similar manner it is easily seen that thegrid 57 oftube'l of channel A is likewise strongly negative since the tube 13 isdrawing plate current from the source 35'connected between the gridresistor 29 of tube 1 and the plate member 87.

Under similar operating conditions to those of signal channels A and B,at the time when tube 11 of channel C tends to pass plate current byreason of the fact that the grid'67 has become positive due to adecrease in voltage drop in grid resistor 31, the condenser 23 isdischarged and, for similar reasons to those previously stated asregards channels A and B, the point 95 becomes strongly negative withrespect to its previous potential. This negative pctential when act- Iis carried toward a positive value, since the point of connection of thegrid 7 2 to the grid resistor 32 has turned a positive value upon thetube 1 1 ceasing to draw plate current from source 36a. Similarly,therefore, the grids 73, 74 and 75 of the tubes 17, 13 and 19 of channelD have likewise all swung positive, and under this condition the tube 17is drawing plate current from the source 36 and the grid 67 of tube 11in channel C is, therefore, placed at a negative value because the pointof connection of the grid resistor 31 to the grid 67 of tube 11 hasbecome negative. Similarly, tube 18 at once commences to draw platecurrent from the source 34 and holds the grid 62 of tube 6 at a negativevalue for the same reason and tube 19 drawing plate currentstill holdsthe grid of the tube 1 at a negative value by reason of the fact thatplate current is being drawn from the source 35. For similar reasons tothose above stated, as soon as the tube 16 tends to draw plate currentthe condenser is discharged and the point 96 which is connected with theB source 33 through the resistance 28 assumes a negative value whichplaces the grid 75 in control of the C battery i8 acting through theresistance 17, and the grid '75 is swung to a negative value. As thegrid 75 swings to a negative value the tube 19 has its plate currentflow substantially decreased and, therefore, the point of connection ofthe grid 57 of tube 1 to the grid resistor 29 is swung to a relativelypositive value because none of tubes 7, 13 or '19 are drawingpiatecurrentfrom source 35. Therefore, the grids 56, 59 and 60 of tubes2, 3 and i are again positive and channel A will once more start tofunction. However, as soon as channel A starts to function, the tubes 2,3 and 4: pass plate current and it may, therefore, be similarly s iownby reference to the description above that the tube 2 will control thegrid '4' 2 of tube 16 to maintain it at a negative value, because tubes2, 8 and 1 each draw plate current from source 36a connected to the gridresistor 32 of tube 16. Similarly the tube 3 will control the grid 67 oftube 11 to maintain it at a negative value since tubes 3, 9 and 1'? alldraw plate current from source 36 connected with the grid resistor 31 oftube 11 and the tube 4, which together with tubes 18 and 12 draws platecurrent from the source connected to the grid resistor of tube 6, willcontrol the grid 62 of tube 6 to maintain it at a negative value untilsuch conditions occur that the con denser 21 is discharged in the mannerfirst described and the grid 62 is carried to a positive value. 7

It is, therefore, seen that thissystein functions alternately andsuccessively to switch from one channel to another and that the rate ofswitching will be totally dependent upon the rate of discharge of therespective condensers 21', 22, 23 and 24L associated with the tubes 1,6,11 and 16 of channels A, B, C, and 1) respectively.

Now that I have described in considerable detail how it is possible toswitch from one channel to another at any predetermined rate of speedsolely governed by the discharging of various condensers of which thecapacity is appropriately chosen, I will endeavor to describe how it ispossible to distribute the time of operation of each channel, so as toset forth clearly the fact that each channel need not, of necessity,work an exact proportion of the total time available, but may have itstime of operation varied in accordance with whether signals are on aparticular channel or not.

It is desirable now to consider the action of the secondary grid members53, 54, and 56 and the tubes 1, 6, 11 and 16, respectively. Each ofthese secondary grids are connected to a signaling circuit, of anydesired or appropriate type, through transformers 98, 99, 100 and 101,or, if desired, through any other suitable coupling such as resistance,impedance, capacity coupling and the like. If it is assumed that thearrangement is being used for facsimile reproduction, it is a well knownfact that the greater part ofany facsimile is composed of what is knownas the whiteportion in contrast to the black portion, as in the case ofa positive print. Therefore, during periods when the white portion of afacsimile is being transmitted it is desirable to maintain the fastestaction through each separate channel over which the white impulsess arepassed and, therefore, lose less time and make other channels availablefor a relatively longer period of time for the marking of the blackpicture impulses. In accordance with the arrangement disclosed, for awhite portion of a facsimile the grid members 53, 5 55 and 56 are swungquite strongly positive, relatively speaking, to the previous potential,and this condition substantially aids the tubes 1, 6, 11 and 16,respectively, to pass a heavy plate current. Consequently the condensers21, 22, 23 and 2% associated with channels A, B, C and D and connectedwith tubes 1, 6, 11 and 16, respectively, are discharged substantiallyimmediately upon the secondary grid members becoming positive, whereasfor the black portion of the picture the time action should be slightlyslower. Therefore, any black impulses in the system, which are producedby black marks on the facsimile, tend to swing the grids of the. varioustubes, heretofore described, less positive (which is practicallyequivalent to a negative value). Therefore, there is a far lessinfluence to a sudden heavy rush of plate current through the first tubeof each channel, and the channel consequently functions in a slower ordelayed manner because the condensers are not obliged to give up theircharge so rapidly.

It may thus be seen, if it is assumed for the moment that channel Aisthe only one-that has a signal, or in other words the only channel overwhich a black portion of the facsimile is being transmitted, that thegrid 53 of tube 1 in channel A is less positive and nearer a zeropotential than the grids 54, 55 and 56 of tubes 6, 11 and 16 of channelsB, C and D respectively. Therefore, the action of the signal passingthrough channel A is somewhat retarded or delayed, but the actionthrough channels B, C and D is considerably speeded up, due to the factthat the condensers associated with each of these latter channels aredischarged almost instantaneously and the tubes of the other channelscontrolled by the various tubes of each of the channels are, in' efiect,blocked so that the minimum of time is lost, but in channel A the time,of course, is somewhat lengthened, due to the fact-that the grid 53 oftube 1: is far lesspositive and the discharge of condenser 21 lessrapid.

Therefore, according to my scheme it is possible toarrange this system,so that if channel A, or any other separate channel, is the only onethat has a signal upon it, that it may utilize approximately 97% of thetime available, and the remaining 3% of the time is equally sharedbetween the remaining three channels, as channels B, C and.

D. v If it is assumed that both channels A and C, or any other twochannels,-

have signals, or in other words are both subjected to black impulses onthe facsimile,then channels A and 0 would share 98% of the time equallyvand the remaining'2% of the time wouldbe equally shared betweentheother two channels, as channels B and iDl If'all four channels are beingused, then each channel would share 25% of the time. It-

will .be noted, therefore, from the. above de scription thatconsiderable time gain and efficiency is accomplished by this type ofgain may be more easily visualized by noting that the use of an ordinarycommutator with only one signal line being energized provides for theuse of only 25% of the available time on that c-hannel, in contract tothe arrangement which has herein been disclosed, wherein as much as 97%of the total time available may be used for any separate channel, de-

pending, of course, upon the definite values of the individualcapacities and resistances used. These values are determined fromcalculations and experiments as will be obvious ance, impedance, orcapacity couplings, and

the output of each of these systems is,-therefore, directly impressedupon the secondary grids above named. It is also possible to utilizethis system for communication of four (as shown) separate messages, sothat if any operator ceases tosend-messages over one channel that thisseparate line will not be idle for as great a time as'otherwise. Thissystem also lends itself to the even distribution of socalled peak loadsby dividing the load equally or proportionately between each of theseparate channels. Y

Associated with each of the tube channels A, B,C and D are the tubes 5,10; 15 and 20, respectively, which have their grid members 61, 66, 71and 76, respectively, connected to thesame input as the grids 60, 65, 702nd 7 5 of tubes4, 9, 14 and 19 except that the grid connection of thetubes 5, 10, 15 and 20 is made ahead of the resistancemembers 37', 40,43 and 46 so that the group of the tubes 5, 10, 15 and 20 will not reacha negative value until some time after the tubes 4, 9, 14, and 19 becomenegative by reason of the fact that the resistances 37,40, 43 and 46must be first overcome. l/Vhen thegrids of,

at 49,. 50, 51 and 52 respectively. The output energy of each oscillatoris fed into an antenna 106 throughtransformers or-other forms ofcouplings generally designated. as

102, 103, 104 and 105; 'The antenna 106 is grounded in any desiredmanner as'at 107.

It is thus seen that as eachchannel is functioning one channel or theother is feeding. its output into the antenna member'106 and it isfurther desirable and a purpose of the invention to have each of theoscillators 49, 50, 51 and 52 feed diiierent tones or frequencies, as,for example, 1,000, 1,300,.

1,500, and 1,900 respectively into the antenna so that four separatechannels each carrying a diiferent frequency are being transmittedineliect (since .the commutation is so rapid) disclosure-as shown by Fig.1, although it is to be understood, as previously stated, that the atall times in accordance with the.

invention is capable of utilizing many more channels thanhave been shownor is also capable of using less channels than four. The battery 97 isshown as a source of potential forrall the oscillators 49, 50, 51 and52. If desired, neon lamps or other glow indica tors 108, 109, 110 and111 may be associated with the output of amplifiers 5, 10, 15 and 20 andthe oscillators 49, 50, 51 and 52 for the purpose of indicating the timerate of change of-the signal carried from one channel to another as wellas to determine whether or not the system is in operation.

Now to make-reference to Fig. 2 of the drawings, a similar arrangementto that of Fig. 1 is shown, with the exception that 1nstead of using thedouble grid tubes, 1, 6, 11 and 16, these are replaced by the threeelectrode tubes 1a, 1b, 10 and 1d, Working in conjunction with the threeelectrode tubes, 112, 113, 11 1, 115 each of which last named tubesreceive the signals from channels, A, B, O and D, respectively. Thetubes 112, 113, 114, 115 have their plate electrodes connected with thesources of potential 116, 117, 118 and 119, respectively, in the usualmanner. In the arrangement of Fig. 2 neon lamps 120, 121, 122 and 123are connected with the output circuits of the tubes 1a, 1b, 1c and 1d aswell as tubes 112, 113, 114 and 115 for a purpose to be hereinafterdescribed.

Referring now to the arrangement shown in Fig. 2, and starting theconsideration with the channel A, as in the previous description of Fig.1, suppose that all the grids of the tubes in channel A are positiveunder which condition all the tubes of this channel draw plate current,as seen from the accompanying diagram, it can be seen that a negativepotential is applied to the grids of the tubes in channels B, C and D,by reason of the voltage drop in the grid resistors of the first tubesin each respective channel caused by tubes 4, 8 and 2 drawing platecurrent from sources 3 1, 36, and 86a, respectively, causes the gridpotential in the grids of tubes 1?), 10 and 1d, respectively, to becontrolled in the same manner as was explained above when makingreference to Fig. 1. This negative potential applied to the grid of thefirst tube in each of channels B, C and D cuts off the plate current inall the tubes in the channels so the output of each channel but that ofchannel A is cut off. In channel A the positive grid (actually of zeropotential but relatively positive) of the first tube 1a, permits thecondenser 21 to charge. The potential of the condenser acts inconjunction with the B battery voltage 33a, which is below theextinction voltage of the neon lamp 120.

When the condenser 21 is fully charged, the additional voltage acrossthe neon lamp 120 is of such a value as to flash the lamp. The purposeof the neon lamp is to cause the condenser potential to vary between twolimits and the time element depends upon how long this differentialpotential builds up with respect to time. The mechanism or constructionof the neon lamp is such that a definite voltageV is necessaryto startthe lamps flashing. Once the lamp flashes, it will continue to remainlit while the potential across it is lowered until a critical voltage Vis reached, under which condition the lamp goes out. V is called thestarting voltage and V the extinction voltage. To start the lampflashing again, the potential must be equal to V and the lamp will notgo out until V is reached.

where t is the time, C is the capacity of the condenser, V is thestarting valtage of the neon lamp, V is the extinction voltage and i isthe charging current. Consequently, from a knowledge of the values of O,V and V the time that any particular channel is on or operating for boththe signal-on and the signal-01f conditions may be fixed a priori byadjusting the charging currents. Incidental to this function of the neonlampthe lamp may also indicate whether the system is functioning if anobserver watches whether or not the flashing operation is occurring.l/Vhen the condenser is discharged a negative potential is applied tothe grid of the tube 4 of channel A by virtue of the voltage drop in theresistor 25 connected to the B battery for reasons similar to thosepreviously stated.

This negative potential stops the plate current from flowing through thegrid resistor of tube 1?) of channel B, which cessation of current flowremoves the negative potential applied to all the grids of channel B andcarries them to a positive potential. In the showing of Fig. 2 the gridsof the tubes are direct connected in a similar manner to thatillustrated by Fig. 1, but all grids connect with the grid resistor ofthe first tube in the channel and are, therefore, all carriedpractically instantaneously to the same potential. INhen this happens,plate current flows and current is cut ofl in channel A in a mannersimilar to that previously described, and continues to hold channels Band D in the off position due to the plate current flowing through thegrid resistor of tubes 1a,, 10 and 1d of channels A, C and Drespectively'by reason of the fact that tubes 7, 9 and 8 draw platecurrent from sources 35, 36 and 86a and complete the circuit through thefilaments of the last named tubes.

The condenser 22 in channel B now begins to charge, and when it ischarged suiticiently to flash the neon lamp 121, channel 0 is placed inan operative position which stops the operation of channel D andlikewise prevents the operation of channels A and B in a manner whichhas been previously disclosed. The action of the tube is then passed onto channel D, and from D to A, and so forth, to complete the cycle ofoperation over and over again.

This commutating action would be at a uniform rate and hence have noadvantage over the ordinary type of commutator if it were not for thesignal tubes 112, 113, 114 and 115 in parallel with the first tubes 1a.1b, 1c and 1d of each channel A, B, C and D. Due to the presence of thetubes 112, 113, 114

and 115 the charging current of the condenser can be varied, and sinceit is the charging time of each condenser that controls the length oftime any separate channel is operating it is evident that if no signalis on the grid of the signal tube this grid is at zero potential, andthe charging current of the condenser is the sum of the plate currentsof the signal'tube 112 and first tube 1a of the channel, if channel A isconsidered. The polarity of the incoming signal voltage applied to thegrid of the signal tube in each channel is such as to make the grid gonegative when the signal comes on. If it is now assumed that a signalhas reached the tube 112, the grid of this signal tube is carried to anegative value so as to cut down substantially and partially cut-ofi theplate current of the signal tube 112, which reduces the charging currentin thecondenser and thus increases the time necessary to charge thecondenser. As a result of this. action, when a signal is received on anyparticular channel the output of the channel is operative for a longertime than when there is no signal,which is readily seen in view of thefact that the charging rate of the associated condenser is slower. By asuitable adjustment of the circuit constants, the time of action, or inother words the charging time of the various condensers can be madeexceedingly short for the no signal condition, and relatively long forthe signal condition. In this manner only channels having signalsimpressed on them could actuate their outputs for any appreciable lengthof time. Thus, a saving of time is effected by substantially keepingonly the signal channels open, and the no signal? channels are used forsuch a small period of time during the cyclic operation of thecommutator that their time of operation can be considered as negligible.

. The remaining connections as shown in Fig.2 are similar to those ofFig. 1, and the. operation functions in a similar manner. It is believedthat it will be clear exactly how the system of Fig. 2 functions whenthe description which is more amplified with respect to Fig. 1 isconsidered.

Therefore, it is believed that it will be clear that by the arrangementherein shown and described, I have provided a system for commutation,wherein there are absolutely no mechanical parts to get outof order, orto prevent quick action, and that a very material advantage is gainedtherefrom, and that a system has been provided in which is preferable.to use a plurality of frequencies for transmission of messages,facsimile .or television, but at the same time a system which may easilybe enlarged to accommodate an indefinite number of signalchannels.

Further, it is believed that while in places the specification hasreferred to picture transmission and signals resulting therefrom, thatthe arrangement will be considered as applicable toany formof multiplexwork or even repetition work and suitable for speech and codetransmission. This invention also particularly adapts itself to use insystems for flashing electric signs where there are a plurality oflights or sets of lights to be flashed on and off at either regular orirregular intervals. In thecase of fiashing signs on and ofii therewould be no essential change over the formof invention shown exceptthat, if dethroughout many claims I specifically intend 7 these terms tobe considered generic and illustrative of all applications rather thanas limiting terms and confined exclusively topicture and communicationwork. I, therefore, desire to limit myself only insofar as the scope ofthe claims necessitate, and believe my invention to cover allmodifications of the above described invention such as fall fairlywithin its spirit and scope as defined in the appended claims.

Having now described ,my invention, I claim 1 1. lhe method of obtainingmultiplex com munication with a plurality of signal channels whichincludes impressing signals upon each of a plurality of signal channels,cyclically varying the time of operation of each of said channels inaccordance with the strength of said impressed signal impulses, andtransmitting energy from said plurality of signal channels in accordancewith said varying time rate of operation.

2. The-method of varying the time operation of a plurality of signalchannels in a multiplex: communication system which includes impressingaplurality of signals upon a series of signal channels, cyclically andsuccessively switching from one to another of said signal channels,controlling the time operation of each of said plurality of signalchannels in proportion to the intensity of the said impressed signals,and controlling a signal transmitter for all of said signalsinaccordance with the time rate of operation of each of said signalchannels. 7 v

3. The method of obtaining multiplex communication with a plurality ofsignal channels which includes impressing signals upon each of saidplurality of signal channels, transmitting the signal energy from eachof said channels, and controlling the time operation of transmission foreach of said chan nels in accordance with the signal intensity impressedupon each of said channels.

Other similar uses I 4. The method of obtaining multiplex communicationwith a plurality of signal channels which includes impressing signals ofdifferent frequencies upon each of a plurality of signal channels,controlling the time operation of each of said signal channels inaccordance with the intensity of the impressed si nals, and successivelyand continuously transmitting the said signals in accordance with thetime operation of each of said signal channels.

5. In a multiplex communication system, a plurality of signal channels,vacuum tubes associated with each of said channels, and closed circuitsso connecting the vacuum tubes in each of said channels as to cyclicallyand periodically'shift from one to another of said signal channels fortime periods varying in accordance with the presence and absence ofsignals impressed upon each signal channel.

6. A communication system comprising in combination a plurality ofsignal channels, a plurality of vacuum tubes associated with each ofsaid signal channels, one of said tubes in each of said signal channelsfunctioning as a control tube for said channel, means provided by saidcontrol tube for delaying the time of action of the particular signalchannel during periods when signals are received and accentuating therate of operationof said signal channels during non-signalling periods,and an antenna system associated with all of said signal channels fortransmitting energy output from said signal channels in accordance withthe rate of operation of said channels.

7 In a multiplex communication system, a plurality of signal channels,means for applying signals to each of said channels, a plurality oftubes in each of saidchannels, said plurality of tubes including onecontrolling tube, means for cyclically changing the grid potential onsaid controlling tube, and means for altering the grid potential on theother tubes of said channel, means for delay ing the time of passage ofa signal through each of said channels for one predetermined conditionof grid potential and accentuating the time of travel of signal throughsaid channel for another predetermined condition of grid potential, anantenna system, and means for coupling each of said signal chan nelswith said antenna system and successively and continuously transmittingthe energy from said channels through said antenna.

8. In a multiplex communication system, a: plurality of signal channels,means for applying signals to each of said channels, a plurality oftubes in each of said channels, said plurality of tubes lncludlng onecontrolling tube means for c CllOElll chan ing the grid potential onsaid controlling tube in accordance with varying strength signalsapplied thereto, and means for correspondingly altering the gridpotential on the other tubes of said channel, means for delaying thetime of passage of a signal through each of said channels for onepredetermined condition of grid potential and accentuating the time oftravel of signal through said channel for another predeterminedcondition of grid potential, a modulator tube associated with each ofsaid signal channels, an antenna system, and means for associating saidmodulator with said antenna and influencing said antenna from each ofsaid modulators in accordance with the time of operation of each of saidmodulators as controlled by the time of passage of signals through eachof said signal channels.

9. In a multiple communication system, a plurality of signal channels,means for applying signals to each of said channels, a plurality oftubes in each of said channels, said plurality of tubes including onecontrollin tube, means for cyclically changing the grit potential onsaid controlling tube, and means controlled by said controlling tube foraltering the grid potential on the other tubes of said channel, meansfor delaying the time of passage of a signal through each of saidchannels for one predetermined condition and accentuating the time or"travel of signal through said channel for another predeterminedcondition, an oscillator associated with each signal channel, means formodulating the frequency generated by said oscillator by said modulatingsystem, an antenna means for radiating the energy output of each of saidoscillators during successive periods of operation of each of said tubechannels.

' 10. In a multiplex communication system, a plurality of signalchannels, means for applying signals to each of said signal channels, aplurality of thermionic relays in each of said signal channels, meansfor maintaining the grid electrodes of all of said thermionic relays ineach channel at a uniform potential, a circuit connecting successivetubes of said plurality of signal channels, means for switching from oneto another or said signal channels in accordance with the potential biason the grids of the tubes in one of said signal channels and an outputcircuit for utilizing the energy transferred through said signalchannels during the said interrupted periods.

11. A communication system including a plurality of signal channels,means for applying signals to said signal channels, a plurality ofthermionic relays associated with each of said signal channels, meansfor maintaining the controlling electrode of each of the relays of eachseparate channel at substantially uniform potential, one of saidthermionic relays in each channel functioning as a controlling relay forthe said channel,

means for connecting successive tubes in sucelements of successivesignal channels, means o for successively and continuously energizingthe various signal channels, and an antenna system associated with allof said'signal channels for successively and continuously transmittingthe energy from each of said signal channels. o I 12. In a communicationsystem, a plurality of signal channels, means for applying signals toeach of saidsignal channels, means for delaying the time of passage of asignal through any of said channels under one predetermined intensity ofsignal strengt and means'for accentuating the time of transfer of asignal through said signal channels for another predetermined intensityof signal strength, and means for successively and continuouslyutilizing the energy from said signal systems. 7 v

13. A multiplex communication system including a plurality of signalchannels, means for applying aplurality of signals to each of saidsignal channels, a'plurality of vacuum tubes associated with each ofsaid signal channels, one of said vacuum tubes in each of said channelsfunctioning as a controlling tube, means for maintaining the gridmembers of 7 all vacuum tubes in each channel at a uniform potential,means for cyclically changing the grid potential of the controlling tubein each channel, means associated with said controlling tube foraltering the grid potential on successive tubes in each of said signalchannels upon a change in grid potential in said controlling tube, anantenna system associated with each of said signal channels, forsuccessively and continuously transmitting cyclically varied energy fromeach of said signal channels. I

14. In a signal energy regulating system, a plurality of signalchannels, a plurality of vacuum tubes in each of said signal channels,means for applying signals to each of said signal channels, circuitsconnecting each of said signal channels for ener izing onevor another ofsaid channels at predetermined intensity and cyclically variedintervals,'mea'ns for cyclically and periodically changing from one toanother of said signal channels at a rate of speed proportionate to thesignal strength introduced on any channel, and an output circuit forutilizing energy from said signal channels transferred thereto at cyclically and periodically interrupted intervals in accordance with the timeof passage of a signal through said signal channels.

15. A communication system comprising in combination a plurality ofsignal channels, a plurality of vacuum tubes associated with each ofsaid signal channels, the number of vacuum tubes in each signal channelbeing equal to the number of signal channels, a controlling tube foreach of said channels, means for cyclically maintaining the grid membersof the tubes in each of said separate signal channels at a uniformpotential, means for cyclically changing the grid potential on the gridof said controlling tube of each signal channel and simultaneouslyaltering the potential on all the grids of the tubes in a succeedingsignal channel, means responsive to signalimpulses received on any ofsaid signal chambers for delaying the time of changing the said gridpotentials on the said con trolling tubes in each channel at periodswhen signals are received and accentuating the rate of change ofpotential during non-signalling periods of any of said channels, meansby which each tube of the tube channel passing current will tend toblock the remaining channels of the system, a modulator tube connectedwith each of said channels and arranged to pass current simultaneouslyto the time when its associated signal channel is actuated, anoscillator connected with the output circuit of each of said modulatingtubes,

and an antenna system associated with all of said oscillators andarrangedto transmit the output energy therefrom.

16. In a communication system, a plurality of signal channels, aplurality of thermionic relays including a controlling relay associ atedwith each of said signal channels, means for applying signals ofdifferent frequency to the thermionic relays of each of said signalchannels, c1rcu1ts connecting the various relays in each of said signalchannels, means for cyclically changing the grid potential on thecontrolling relay in each of said channels, and'means provided by saidconnecting circuits between the elements of said signal channels forswitching from one to another of said channels at predetermined periodsgovf erned by signal intensity reaching said channels, an oscillatorassociated with each of said signal channels, and an output circuit forutilizing the energy from said oscillator at predetermined intervalsoftime governed by the time of passage of signals through said signalchannels. l7. Ina communication system, a plurality of signal channelseach including a plurality of vacuum tubes, means for introducingsignals of different frequency upon each of said signal channels,circuits connecting the various elements of each of said channels andproviding a connection between the various elements ofeach of saidchannels, means including a glow-discharge lamp for controlling the timeof operation of each of said channels, and means for successively andcontinuously utilizing the energy from each of said signal channels.

18. I In a multiplex communication system,

a plurality of signal channels each including a plurality of vacuumtubes, circuits connecting each of said signal channels and associatingthe controlling element or" one yacuum tube t each signal channel withat least one tube of each other channel, glow lamp means for controllingthe time of operation of each 5 of said signal channels in proportion tothe signal intensity reachingsaidsignalchannels, and a load circuit forsuccessively and continuously receiving energy from each of said signalsystems.

19. In a multiplex communication system, a plurality of signal channels,a plurality of vacuum tubes associated with each of said signalchannels, a controlling tube for each of said signal channels, circuitconnecting each of said signal channels with each other and associatingthe plate elements of the various vacuum tubes of said channels and thegrid elements of the controlling tubes of each of said signal channels,and glow lamp means for controlling the time of operation of each ofsaid signal channels in proportion to the signal intensity reaching thecontrol tube of each of said channels, and means for successively andcontinuously transmitting energy from said signal channels.

20. In a multiplex comnninication system, a plurality of signalchannels, a plurality of vacuum tubes associated with each of saidsignal channels, a controlling tube in each of said signal channels,means for introducing signals of dillerent frequencies upon each of saidsignal channels, means for cyclically and at interrupted intervalscontrolling the grid potentia-lon the controlling tube in accordancewith the signal strength applied, a modulator associated with each ofsaid signal channels, an oscillator of different frequency associatedwith each of said signal channels, a common load circuit for all of saidoscillators, means for associating each of said oscillators with saidcommon load circuit, means provided by said modulator for modulatingenergy generated by said oscillator in accordance with the signalstransmitted through said signal channels and means for cyclically,successively, and at variable rates of speed governed in accordance withthe signal intensity applied to said signal channels controlling thetime of action of said oscillators upon a said common load circuit. v

21. In a multiple: communication system, a plurality of signal channels,a plurality of vacuum tubes included in each of said signal channels, acontrolling tube for each of said signal channels, a grid resistorassociated with each of said controlling tubes, means for cyclicallychanging the grid potential upon each of said controlling tubes atperiods when signals reach the same whereby for predetermined signalstrengthpredetermined grid potentials are established, means provided bysaid controlling tube for correspondingly changing the grid potential 65on all the other tubes of each of said signal channels, means providedby variations in signal strength reaching each of said controllingtubesior proportionately delaying and accentuating the time of signaltravel through each of said signal channels, an oscil 7 lator ofdifferent frequency associated with each of said signal channels, acommon load circuit associated with all of said oscillators,

and means provided by said time controlled signal channels forcontrolling the time of"7f5 operation of each of said oscillators uponsaid load circuit.

22. The system claimed in claim 21 comprising, in addition, means forconnecting one tube or each signal channel with the grid -BD resistor ofthe controlling tube of each other signal channel whereby the time or"operation of each of said signal channels is controlled in accordancewith the potential drop occur ring through said grid resistor.

23. The system claimed in claim 21 comprising, in addition, means forassociating one tube in each signal channel with one tube of each otherchannel and regulating the potential bias on the controlling tube ofeachQO other signal channel in accordance with the current strength ineach of said tubes.

24:. The method of obtaining multiplex communication with a plurality01" signal channels which comprises impressing signalsfifi upon each ofa plurality of signal channels, directing the si 'nals by commutating toeach of said channels for time periods varying in accordance with thestrength of said impressed signal impulses, and transmitting energy fromsaid plurality of signal channels in accordance with said varying timerate of operation.

25. The method of operating a plurality of signal channels in amultiplex communi cation system which comprises impressing signals uponeach of the plurality of signal channels, sequentially directing thesignals by commutating between said plurality of signal channels, andvarying the time period of commutation for each of said plurality ofsignal channels in proportion to the intensity of the signal impressedthereon.

26..The .method of obtaining multiplex communication with a plurality ofsignal channels which comprises impressing signals upon each of aplurality of' signal channels and cyclically varying the time ofoperation of each of said channels in accordance with the strength ofsaid impressed signal impulses for transmitting energy from saidplurality of signal'channels in accordance with said varyingtime rate ofoperation.

27. l he method of operating a plurality of signal channels in amultiplex communication system which comprises impressing si nals uponeach of the plurality of signal channels, sequentially switching fromone to another of said signal channels, and varying the time operationof each of said piu- L30 rality of signal channels in proportion to theintensity of the signal impressed thereon.

28. The method of operating a series of signal channels in a multiplexcommunication system which comprises impressing signals of difierentcharacteristics uponeach of the series of signal channels, sequentiallyswitching from one to another of said signal channels, and varying thetime period of passage of signals through each of the signal channels inproportion to the intensity of the signal impressed thereon.

29. The method of obtaining multiplex communication with a plurality ofsignal channels which includes impressing signals of differentcharacteristics upon each of the plurality of signal channels,transmitting the energy passed through each of the signal channels, andvarying the time operation of the transmission period for each of thesaid signal channels in accordance with the signal intensity of each ofthe distinct signals impressed on each or" the signal channels.

30. The method of obtaining multiplex communication with a plurality oftone signal channels all coordinated with a single transmission systemwhich includes impressing signals of different tone frequencies uponeach of the plurality of signal channels, controlling the time period ofpassage of signals through each of the signal channels in accordancewith the signal intensity of the individually impressed tonefrequencies, and sequentially transmitting signals from each of thechannels for time periods varying in accordance with the time operationof each of the channels,

31. A thermionic relay system for multipleX telegraphy comprising avacuum tube circuit for each signal channel and closed circuits soconnecting said vacuum tube circuits as to cyclically and periodicallycause said vacuum tubes to become operative for variable time periods.

32. A thermionic relay system for multiplex telegraphy comprising avacuum tube circuit for each signal channel and circuits so connectingsaid vacuum tube circuits as to cyclically and periodically cause saidvacuum tubes to become operative for time periods of durationsproportional to the relative signal intensity on each'of the signalchannels.

33. A thermionic relay system for multiplex telegraphy comprising avacuum tube circuit for each of a plurality of signal channels andclosed circuits so connecting all 01": said vacuum tube circuits as tocause each of said vacuum tube circuits to become se quentiallyoperative for predetermined variable time periods.

34. A thermionic relay system for multiplex telegraphy comprising avacuum tube circuit for each of a plurality of signal channels andcircuits so connecting each of said thereon.

tube circuits in accordance with the signal circuits .as to sequentiallycause one of said vacuum tube circuits to become operative and theremainingtvacuum tube c1rcu1ts 1noperative, and means for varying thetime period of operation of each of said vacuumstrength of theindependent signals impressed on each of the vacuum tube circuits. 36. Acommunication system. comprising in combination a plurality of signalchannels each including a plurality of vacuum tubes,means for impressingdistinct signals upon each of the si nal channels, circuits connectingthe vacuum tubes of each of said circuits so as to. form aninterconnected net work, means for sequentially switching between saidvarious signal channels so as to cause one of said channels to becomeoperative and the remaining channels inoperative, and means for Varyingthe time operation of each of said channels in accordance with thestrength of signal energy impressed thereon.

37. A thermionic relay system for multiplex telegraphy comprising aVacuum tube circuit for each of a plurality of signal channels, circuitsso connecting said vacuum tube circuits as to sequentially cause one ofsaid vacuum tube circuits to become operative and the remaining'vacuumtube circuits inoperative, and capacity means for varying the timeperiod of operation of each of said vacuum tube circuits in accordancewith the signal strength of the independent signals impressed on each ofthe vacuum tube circuits.

38. A communication system comprising in combination a plurality ofsignal chan- .nels each including a plurality of vacuum tubes, means forimpressing distinct signals upon each of the signal channels, circuitsconnecting the vacuum tubes of each of said circuits so as to form aninterconnected net work, means for sequentially switching between saidvarious signal channels so as to cause one of said channels to becomeopera- 2 tive and the remaining channels inoperative,

pressing independent signals upon each of said channels, circuitsconnecting the vari ous tubes of all of said channels so as to form aninterconnected net work, means for transmitting the energy impressed onall of 7 said signal channels, and means for Varying the rate oftransmission of the said energy in accordance with the intensity of theindependent signals impressed on said channels.

40. An electronic relay system comprising in combination a plurality ofsignal channels, a plurality of vacuum tubes associated with each of thesignal channels, one of the tubes in each of the channels functioning asa control tube for the channel, means provided by the control tube fordelaying the time of action of the particular signal channel during timeperiods when signals are supplied and accentuating the rate of operationof the signal channel during non-signaling periods, and a load circuitassociated with all of the signal channels for utilizing the combinedenergy output from the signal channels in accordance with the rate ofoperation of .the individual channels.

RICHARD HO'WLAND RANGER.

CERTIFICATE OF CORRECTION.

Patent No. 1,873, 785.- August 23, 1932.

RICHARD HOWLAND RANGER.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 5,line 50, for "contract" read "contrast"; page 6, line 73, for themisspelled word "valtage" read "voltage"; page 9, line 76, claim 15, for"chambers" read "channels"; and that the said Letters Patent should beread with these corrections therein that the same may conform to therecord of the case in the Patent Office.

Signed and sealed this 10th day of January, A. D. 1933.

M." J. Moore," (Seal) Acting Commissioner of Patents.

